Peter Kasten^a, Severin Zimmermann^a, Manish K. Tiwari^a, Bruno Michel^b, Dimos Poulikakos^a,*

Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-10, 2010, DOI:10.5098/hmt.v1.2.3006

Abstract Electronic data center cooling using hot water is proposed for high system exergetic utility. The proof-of-principle is provided by numerically modeling a manifold micro-channel heat sink for cooling microprocessors of a data center. An easily achievable 0.5l/min per chip water flow, with 60°C inlet water temperature, is found sufficient to address the typical data center thermal loads. A maximum temperature difference of ~8°C was found between the solid and liquid, confirming small exergetic destruction due to heat transport across a temperature differential. The high water outlet temperature from the heat sink opens the possibility of More >

Li Chen, Hui-Bao Luan, Wen-Quan Tao^*

Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-11, 2010, DOI:10.5098/hmt.v1.2.3002

Abstract Multi-phase lattice Boltzmann method is applied to investigate liquid water transport in th GDL and GC. The liquid water transport processes in the GDL, near the GDL-GC interfaces and in the GC are discussed. The effects of channel land on liquid water dynamic behaviors and distribution in the GDL and GC are investigated. It is found that channel land covers the GDL-GC interface where liquid water reaches changes the water distribution near the GDL-GC interface and in the GC. While channel land is apart from the GDL-GC interface where liquid water reaches changes the effects More >

G. Prakash Narayan^a, Karan H. Mistry^a, Mostafa H. Sharqawy^a, Syed M. Zubair^b, John H. Lienhard V^a,†

Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-13, 2010, DOI:10.5098/hmt.v1.2.3001

Abstract Simultaneous heat and mass exchange devices such as cooling towers, humidifiers and dehumidifiers are widely used in the power generation, desalination, air conditioning, and refrigeration industries. For design and rating of these components it is useful to define their performance by an effectiveness. In this paper, several different effectiveness definitions that have been used in literature are critically reviewed and an energy based effectiveness which can be applied to all types of heat and mass exchangers is defined. The validity and the limitations of the various effectiveness definitions are demonstrated by way of several examples More >

Bengt Sundén^*, Jinliang Yuan

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-20, 2010, DOI:10.5098/hmt.v1.1.3008

Abstract Depending on specific configuration and design, a variety of physical phenomena is present in fuel cells, e.g., multi-component gas flow, energy and mass transfer of chemical species in composite domains and sites. These physical phenomena are strongly affected by chemical/electrochemical reactions in nano-/micro-scale structured electrodes and electrolytes. Due to the electrochemical reactions, generation and consumption of chemical species together with electric current production take place at the active surfaces for all kinds of fuel cells. Furthermore, water management and twophase flow in proton exchange membrane fuel cells (PEMFCs) and internal reforming reactions of hydrocarbon fuels More >

R. J. Johnson^∗, R. Pitchumani^†

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-9, 2010, DOI:10.5098/hmt.v1.1.3007

Abstract Much research is currently being performed with carbon nanotube additives to neat resin systems to enhance properties such as thermal and electrical conductivity, strength, modulus and damping. Fabrication of parts based on carbon nanotube filled resin systems requires information on their cure kinetics and rheology, which has been relatively less studied so far. This work presents an extensive experimental study that systematically characterizes the cure kinetics and viscosity as a function of degree of cure and temperature of EPON 815C/EPICURE 3274 epoxy resin system laden with carbon nanotubes. Studies are conducted to determine the effects More >

Po Ting Lin, Hae Chang Gea, Yogesh Jaluria^*

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-20, 2010, DOI:10.5098/hmt.v1.1.3003

Abstract Thermal systems play significant roles in the engineering practice and our lives. To improve those thermal systems, it is necessary to model and optimize the design and the operating conditions. More importantly, the design uncertainties should be considered because the failures of the thermal systems may be very dangerous and produce large loss. This review paper focuses on a systematic strategy of modeling and optimizing of the thermal systems with the considerations of the design uncertainties. To demonstrate the proposed strategy, one of the complicated thermal systems, Chemical Vapor Deposition (CVD), is simulated, parametrically modeled,… More >

Chen Fang^*, Milnes David, Anita Rogacs, Kenneth Goodson

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-11, 2010, DOI:10.5098/hmt.v1.1.3002

Abstract Vapor-venting microchannel heat exchangers are promising because they address the problems of high pressure drop, flow instability, and local dryout that are common in conventional two-phase microchannel heat sinks. We present a 3D numerical simulation of the vapor-venting process in a rectangular microchannel bounded on one side by a hydrophobic porous membrane for phase-separation. The simulation is based on the volume of fluid (VOF) method together with models for interphase mass transfer and capillary force. Simulation shows the vapor-venting mechanism can effectively mitigate the vapor accumulation issue, reduce the pressure drop, and suppress the local More >

Je-Chin Han^*, Akhilesh P. Rallabandi

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-21, 2010, DOI:10.5098/hmt.v1.1.3001

Abstract Film cooling is widely used to protect modern gas turbine blades and vanes from the ever increasing inlet temperatures. Film cooling involves a very complex turbulent flow-field, the characterization of which is necessary for reliable and economical design. Several experimental studies have focused on gas turbine blade, vane and end-wall film cooling over the past few decades. Measurements of heat transfer coefficients, film cooling effectiveness values and heat flux ratios using several different experimental methods have been reported. The emphasis of this current review is on the Pressure Sensitive Paint (PSP) mass transfer analogy to More >

GRACIELI DALLA NORA¹, TAMARA PASTORI¹, HAYWOOD DAIL LAUGHINGHOUSE IV^2,3, THAIS SCOTTI DO CANTO-DOROW¹, SOLANGE BOSIO TEDESCO^1*

BIOCELL, Vol.34, No.3, pp. 95-102, 2010, DOI:10.32604/biocell.2010.34.095

Abstract Mikania glomerata is a plant used in Brazilian traditional medicine, known as ‘guaco’. It possesses anti-inflammatory properties and the aqueous extracts of its leaves are indicated for the treatment of diseases of the respiratory tract. This study aimed at evaluating the antiproliferative and genotoxic effect of Mikania glomerata leaf infusions on the cell cycle of onion. The material used was collected in the native environment from Rio Grande do Sul State, Brazil. Aqueous extracts through infusions were prepared in two concentrations: 4g/L (usual concentration) and 16g/L (4x more concentrated) of each of the populations. Two groups of… More >

VALERIA C. DENNINGHOFF^1,2*, GEORGINA P. OSSANI¹, ANA M. UCEDA¹, MARIA A. AVAGNINA², BORIS ELSNER², ALBERTO J. MONSERRAT¹

BIOCELL, Vol.34, No.2, pp. 65-70, 2010, DOI:10.32604/biocell.2010.34.065

Abstract Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter More >